Has Anyone Else Seen Butterflies Chasing Away Other Butterflies or Birds?

In early June I was walking in a park in southern Ontario hoping to hear a certain warbler singing. That meant I spent a long time pacing up and down a short stretch of path admiring all the insects, reptiles and birds to be seen while I listened. My reward was not the emergence of the wanted warbler but instead a first-hand look at a truly intriguing encounter between a Swallowtail and a Robin.

Tiger Swallowtail butterflies are common in June. They are primarily interested in finding partners and/or laying eggs but they do sometimes stop to sip from flowers, sap, waste or puddles. So I kept an eye on a butterfly when it floated low over the still-wet-from-last-night’s-rain path.

To my astonishment, the Tiger Swallowtail began to try to drive an American Robin away from a particular part of the path!

Photo of Swallowtail Vs Robin D on NaturalCrooksDotCom

Swallowtail Butterfly Attacks Robin to Try to Drive It Away

The Robin, which had been moving up and down the path hunting had paused beside what turned out to be a clump of wet, dead, slightly rotten vegetation. As it turned out later, the butterfly wanted to land on that sodden lump.

Photo of Swallowtail Vs Robin A on NaturalCrooksDotCom

Not just once, or twice, but repeatedly, the Swallowtail dove at the Robin. It came within a few cm (inches) several times. The butterfly would circle past the bird and come back again very quickly. I actually watched the Robin flinch, twice, when the Tiger came very close.

Photo of Swallowtail Vs Robin B on NaturalCrooksDotCom

After more than 2 minutes of these aerial attacks, the Robin eventually moved a few steps away, although I’m not convinced that it even knew what the Swallowtail wanted.

Photo of Swallowtail Vs Robin C on NaturalCrooksDotCom

Very soon after it departed, the Tiger Swallowtail settled onto the wet clump of leaves and sipped delicately. It stayed there for four minutes “drinking.” I paced, slowly and carefully, around it taking photos and it did not budge.

Photo of Swallowtail Vs Robin E on NaturalCrooksDotCom

Eventually, the butterfly moved up onto a leaf on a nearby shrub and basked. A few minutes later it left.

Photo of Swallowtail Vs Robin F on NaturalCrooksDotCom

Why Didn’t the Robin Move Sooner?

I’m not certain but it seemed like the Robin was interested in catching other insects near and in the sodden leaves.

Photo of American Robin Snack on NaturalCrooksDotCom

Do Butterflies Often Mob Birds?

It took a bit of searching but I have found other reports of mobbing behaviour from butterflies. There seem to be three common types:

Some Butterflies Will Defend Their Territories from Other Butterflies and Other Creatures

Red Admirals are known to be territorial in some situations. I had one come after me the other morning: It flew straight at me, then swerved and fluttered briefly around my camera lens. I’m still not sure if it was bothered by me or if it saw a reflection in my lens and thought it was chasing another butterfly.

Others report attacks by Red Admirals as well. James C. Trager, in the comments on the Prairie Ecologist website, says he has seen Hackberry Butterflies chasing anything large that flies into their territory.

Some Butterflies Will Defend Their Food Source

This is what I think the Swallowtail I watched was doing. It wanted to land on the wet dead leave mass and ingest the wet juices possibly to get minerals. The Robin was in its way so it drove it off and then very quickly landed and stayed perched even when I came quite close to take photos.

Other people report seeing this type of behaviour to defend flowers, sap and mud puddling sipping spots.

For example, the Prairie Ecologist, Chris Helzer, wrote on his website about Gray Copper Butterflies driving Regal Fritillaries away from milkweed flowers.

Some Butterflies Will Attack Other Butterflies

On the Prairie Ecologist’s website, in the comments, several readers reported that they had witnessed Fritillaries attacking Monarchs. They had even seen the Fritillaries landing on Monarchs as they emerged from their chrysalises. This damaged some of the Monarchs that had not yet pumped up their wings and hardened their bodies.

And Yes, Other People Have Seen Butterflies Chasing Birds

Tom H., in the comments on the Prairie Ecologist website, reports having seen a Common Banded Skipper chasing a Hummingbird away.

Steven M,. also in the comments, had seen a Monarch go after birds.

Marie Winn reports on her Central Park Nature News website that Ben Cacace watched a Swallowtail drive a pair of mallards into the water. The butterfly apparently actually struck the Mallard more than once on the head.

On BirdForum, a chat site for bird watchers, one person reported seeing Purple Emperors chasing birds, and another reported seeing a butterfly chasing a swallow.

In the comments on a Flickr photo of a Lorquin’s Admiral Butterfly, a reader confirms that they will attack birds.  The Canadian Biodiversity Information Facility website posting for this Admiral also states this “This is a very pugnacious butterfly, often attacking any intruder in its territory, even large birds.” It cites a reference from 1981.

Photo of Eastern Tiger Swallowtail on NaturalCrooksDotCom
The Victor basking in its success.

So I’m not the first person to see this curious behaviour. I found it quite interesting to watch and at times amusing, too. I hope I’ll see a repeat engagement on another spring morning.

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Have you seen butterflies chasing away birds, other butterflies, or other creatures? Please share your experience with a comment.

10 thoughts on “Has Anyone Else Seen Butterflies Chasing Away Other Butterflies or Birds?

  1. Last weekend I saw a tiger swallowtail harassing a redwing blackbird perched on a milkweed flower. I was astounded but I guess that is not the first sighting of butterfly aggression.

  2. Today, Nov 8, 2015, I saw a butterfly chasing a bird. It was at Coronado-del Sol HS in Tempe, AZ. Every now and then, the bird would turn and try to attack the butterfly, but the butterfly was better at manouvering in small spaces and the bird couldn’t catch it. Then the bird would turn and fly away, with the butterfly in pursuit. Couldn’t say what kind of bird or butterfly but I’ve never seen anything like this before.

    • Wow! That’s one determined butterfly. I had never seen it before either. It’s quite amazing to see what we think of as a delicate fragile butterfly attacking a creature as large and strong as a bird. Thank you for sharing your sighting!

  3. I witnessed a butterfly chasing 2 swallows in san diego around a pool at a resort today. I was amazed. The 2 birds came back several times and each time the butterfly came from somewhere and chased them non stop in circles around the pool. It was quite a show. I saw the butterfly land on one of the big tropical leaves in the same spot at least 3 times, so maybe it was being territorial? The birds did not try and fight back at all.

  4. I live in San Diego and have swallowtails who never appear to feed. They have always been aggressive towards each other, but yesterday I saw the dominant swallowtail chasing hummingbirds. My biggest concern, however, is that I have added milkweed and a butterfly garden and this swallowtail is chasing my monarchs away. Is there anything that I can do?

    • I don’t think there is much you can do, but such strong territorial behaviour likely won’t last too long as the breeding season for the swallowtails isn’t too long. Most monarchs near here will move over a flower or two but aren’t really that easy to chase off. Hopefully yours will push back too. Thanks for sharing your sighting!

  5. Just witnessed three Great Spangled Fritillaries chasing away a tree swallow when it came close to “their” coneflowers. Quite impressive to witness. Didn’t know it was possible and then found this site

    • Wow! that sounds like quite a ‘gang’ of Fritillaries. Thank you for sharing your sighting of another act of butterfly assertiveness!

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